Approach to diagnosing pregnancy

3 reasons we want to do pregnancy diagnosis

1. rapid identification of fertility

2. assist with production system

3. satisfy curiosity

what is the general principle that confirms pregnancy in most species?

• non-return to oestrus

in which species does not returning back to oestrus NOT indicate pregnancy?

• dog

why is using no-return to oestrus not reliable?

• missed observation

• pathological conditions

• short oestrus-oestrus interval

what causes pregnancy failure in the mare b/w days 1-5? will she return back to oestrus

• loss whilst in the tube → normal oestrus cycle

what enables the mare to return back to oestrus following pregnancy loss b/w day 5-15

• no maternal recognition of pregnancy - unless there’s uterine inflammation, she’ll return back to cycling

how many types of pesudopregnancy are there in teh mare?

• 2

how can we treat type 1 pseudopregnancy in the mare?

• Prostaglandin PGf2a

can we treat type 2 pseudopregnancy in the mare with PGF2a, why?

• no - endometrial cups need to disintegrate, not reliant on CL

what are the 4 categories of pregnancy diagnosis

1. protein/endocrinological change

2. detection of foetus/foetal membranes

3. physical changes in dam

4. secondary maternal changes

what test of progesterone helps confirm pregnancy?

• elevated progesterone after day 21 of mating

is using progesterone levels after mating reliable as a pregnancy diagnosis?

• no - false positives and negative may be possible

what is the most reliable way to use progesterone to confirm pregnancy?

• take frequent samples

can we use oestrogens to detect pregnancy?

• yes we can use foeto-placental oestrogens which are only synthesised if the animal is pregnant

why do we not want to use feto-placental oestrogens as a detection method for pregnancy?

• because it’s mid-late gestation that these appear

what is the hormone used for PD in bitch and queen?

• relaxin

what hormone can we use in cows to confirm pregnancy, that’s not P4?

• placental lactogen

what methods can we use in rectal palpation to determine pregnancy?

1. pregnancy specific uterine enlargement

2. oedematous uterus feeling

3. uterus has moved more ventrally

4. membrane slip in the cow - NOT advised

5. ballottement of the foetus

how can we use abdominal palpation to confirm PD?

• to palpate the foetus

  • detect uterus enlargement

what are 2 ultrasound modes we can use to detect pregnancy?

• simple doppler - trans-abdominally

• B-mode real-time - transabdominal or transrectal

for whcih species will we use transabdominal B-mode real time imaging?

• dogs, cats - species you can’t do rectal ultrasound for

how will a conceptus appear on ultrasonography?

• anechoic structure

why is it important to be methodical when ultrasounding a mare’s uterus?

• need to ensure that there' aren’t twins present - due to the complications it poses

how would we remedy finding a twin pregnancy on ultrasound?

• popping oen of the conceptuses

what may we use to confirm pregnancy in a cow around day 28, or later?

• foetal heart beat

in late pregnancy, what may we use to confirm presence of a pregnancy?

• more developed foetal structues e.g. limb buds - especially if wanting to do sex determining

what other structure needs to be present to confirm a pregnancy when doing transrectal ultrasound?

• CL

during late gestation, what alternative method to ultrasound can we use?

• radiography - due to skeleton mineralisation

what 4 physical changes may we see in the mother associated with pregnancy?

• increased appetite

• weight gain

• abdominal enlargement

• relaxation of perineal tissue

what are 2 physical changes that are indicative of pregnancy?

• auscultation of foetal heart beats

• uterine artery enlargement

what changes do we see in the uterine artery used to confirm pregnancy?

• enlargement

• change in blood flow to fremitus

what is ‘fremitus’ and what are we referring to?

• a turbulent buzzing in the uterine artery during pregnancy

what are 2 external chagnes we may see associated with pregnancy?

• non-return to oestrus

• teat and mammary gland changes

what teat and mammary gland changes may we observe in a pregnant individual?

• reddening

• enlargement

• secretion of milk in late pregnancy

• ‘waxing up’ in the last weeks of gestation

in which species is using enlargement of mammary tissue not reliable?

• dog and cow - except for first calving

what chagnes will we see to the cervix during pregnancy, why?

• dry and tacky mucous due to prolonged elevation of P4

what changes may we see to the vaginal wall during pregnancy?

• thinning due to the prolonged progesterone

for a cow pregnancy timeline when would we expect to notice/perform:

1. non-return to oestrus

2. trans-rectal ultrasound

3. transrectal palpation

4. transrectal foetal ballotment

5. palpation of cotyledons

6. uterine artery fremitus

7. foetus palpation transrectally

1. d18-24

2. d28 +

3. d35+

4. d50+

5. d80+

6. d105-210

7. d120+

For the following, please order them from best to worst for early PD testing in the cow:

1. trans-rectal ultrasound

2. rectal palpation

3. early conception factor

4. milk progesterone

1. early conception factor

2. milk progesterone

3. transrectal palpation

4. rectal palpation

For the following, please order them from best to worst for accuracy of PD testing in the cow:

1. trans-rectal ultrasound

2. rectal palpation

3. early conception factor

4. milk progesterone

1. trans-rectal ultrasound

2. rectal palpation

3. milk progesterone

4. early conception factor

For the following, please order them from best to worst for negative diagnosis accuracy when PD testing in the cow:

1. trans-rectal ultrasound

2. rectal palpation

3. early conception factor

4. milk progesterone

1. trans-rectal ultrasound/rectal palpation

2. milk progesterone

3. early conception factor

are what time would we expect to know a ewe had failed to be raddles

• d16-19

when would we transabdominally ultrasound a ewe, what would we want to find?

• from d30

• detection of fluid filled uterine horn - later detection of cotyledons/caruncles

when would we transabdominally ultrasound a ewe for pregnancy number confirming?

• d45-80

what 3 things can we detect in a ewe fromd ay 80 to confirm pregnancy/

• foetal pulse with doppler ultrasound

• palpation of caudal uterine artery

• pregnancy cervical mucous

what 2 things can we detect in the ewe from day 100 to confirm pregnancy?

• enlargement of abdomen and udder

• transabdominal ballottement of foetus

when would we expect a sow to fail to return to oesturs

• day 18-24

when would we detect elevated plasma progesterone in a sow?

• day 22-24

when would we be able to detect elevated plasma oestrone sulphate?

• day 25

from what day could we transabdominally ultrasound a sow?

• day 20

when could we detect foetal pulse in a sow?

• day 30

what 2 things can we detect at day 40 in a sow?

• transrectal uterine artery fremitus

• vaginal biopsy - look at vaginal layers

what do we do in the following days for a mare pregnancy daignosis:

1. d12-15, 21, 35

2. from d21

3. d60-120

4. from d80

5. d150

1. transrectal ultrasound

2. transrectal palpation

3. plasma eCG

4. foetal ballottement

5. plasma or urine oestrogen

what do we do at the following days to confirm pregnancy in the bitch:

1. from d25 (2)

2. from d28

3. from d45

4. from d50

1. transabdominal ultrasound and plasma relaxin

2. abdominal palpation for swelling

3. radiographic examination

4. transabdominal foetal ballotement

in the queen what do we do at the following days for PD:

1. d25

2. d25

3. d28

4. d45

5. d50

1. transabdominal ultrasound

2. plasma relaxin

3. abdominal palpation for discrete swelling

4. radiographic exam

5. transabdominal foetal ballotment